TCP connection not closing properly leading to dangling CLOSE_WAIT state and system overload

Tái hiện cả hai trường hợp bằng Python 3.10.15, databricks-sql-python 3.1.2, các lệnh gọi sql.connect được hiển thị và netstat để quan sát trạng thái socket. Hoàn tất khi các kết nối được đóng đúng cách sau context manager hoặc các lệnh gọi close rõ ràng, không có socket CLOSE_WAIT nào bị giữ vô thời hạn và tài nguyên phía client được giải phóng.

Testcase 1

Python 3.10.15 (main, Sep  7 2024, 18:35:33) [GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from databricks import sql
>>> sql.__version__
'3.1.2'
>>> with sql.connect(server_hostname = "<HIDE>", http_path = "<HIDE>", access_token = "<HIDE>") as connection:
...     with connection.cursor() as cursor:
...             cursor.execute("select * from table")
...             column_names = [desc[0] for desc in cursor.description]
...             query_out = [dict(zip(column_names, row)) for row in cursor.fetchall()]
...             
... 
<databricks.sql.client.Cursor object at 0x7f88551c14e0>
>>> query_out
[{"sometime" : "something}]


On the sidelines, the network connection for this process (after with clause gets finished), remain in ESTABLISHED state and then moves to CLOSE_WAIT state indefinitely. 

Every 1.0s: netstat -apn | grep 1070099                                                                                          asinha-vm-ubuntu-20-04-1: Wed Nov 20 02:43:13 2024

tcp       25      0 10.5.220.4:58078        so:me:ip:add:443      CLOSE_WAIT  1070099/python3

Testcase 2

Python 3.10.15 (main, Sep  7 2024, 18:35:33) [GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from databricks import sql
>>> sql.__version__
'3.1.2'
>>> connection = sql.connect(server_hostname = "<HIDE>", http_path = "<HIDE>", access_token = "<HIDE>")
>>> ## at this point a TCP connection got made as ESTABLISHED state ##
>>> cursor = connection.cursor()
>>> cursor.execute("select * from table")
<databricks.sql.client.Cursor object at 0x7f9d65db26b0>
>>> column_names = [desc[0] for desc in cursor.description]
>>> query_out = [dict(zip(column_names, row)) for row in cursor.fetchall()]
>>> cursor.close()
>>> connection.close()
>>> # even after close being called, the connection remains in ESTABLISHED state (for a long time) and then finally moves to CLOSE_WAIT state, which never changes.

Every 1.0s: netstat -apn | grep 1074808                                                                                          asinha-vm-ubuntu-20-04-1: Wed Nov 20 02:49:36 2024

tcp       25      0 10.5.220.4:53810        so:me:ip:add:443      CLOSE_WAIT  1074808/python3

Connections should be closed properly, and all client resources should be freed properly.